One of the worst defensive showings in 60 seasons of Vikings football apparently has convinced an old dog it's time for some new tricks.

"The offenses have changed so much the last four or five years," Mike Zimmer, the Vikings' 64-year-old defensive-minded head coach, said Wednesday. "It's time that we need to do some things differently and change and adapt [defensively]. … Some of it is big change, some of it is minor tweaks."

Zimmer's 475 points allowed last year were nine short of the worst mark in team history. Only six other times have the Vikings allowed 400 points. Three came in the team's first six seasons, before Bud Grant arrived from Canada. One came during the infamous Les Steckel season of 1984. And the other two got Leslie Frazier fired and Zimmer hired.

So, yeah, even though injuries clobbered last year's defense, Zimmer's postseason autopsy also revealed the need for some schematic changes he plans to unveil this fall. So now the guy who years ago was credited with popularizing Double-A gap pressure packages admits he needs to catch up to the game's offensive minds.

"The No. 1 thing we want to do on defense is we want to play fast, we want to play physical, we don't want to be thinking," Zimmer said in his first news conference since the end of the 2020 season.

"The offenses lately have been getting us to think because we have to adjust here, adjust there, do this, do that. Some of these things we've talked about, and it's just too hard to implement during the season."

Zimmer said the league hasn't told him whether offseason training will be in-person or virtual as it was last year because of COVID-19. For now, he's just enjoying the benefits of his coaching staff being able to sit together, watch film and brainstorm at TCO Performance Center.

"We've had some of the best meetings that I've had in eight years, probably," Zimmer said. "We're dissecting every little thing that we do. Going through everything with a fine-tooth comb. I've been really impressed with the coaches. … If we were in 12 different cities doing this in a Zoom meeting, we couldn't get this done."

The Vikings have signed six free agents from other teams this offseason, and all six are defenders. Three of them — tackle Dalvin Tomlinson, cornerback Patrick Peterson and safety Xavier Woods — will be starters while Mackensie Alexander could return to his role as the nickel slot corner after a year in Cincinnati.

"Our offense has been pretty darn good; they were sixth in the league last year," Zimmer said. "We do have some holes that we have to fill [on offense]. There's still time to do that. … But when we evaluated the defense after the season, it was pretty barren in there. So we had to address that."

As he was evaluating the dismal 2020 season, Zimmer knew he'd be getting stars Anthony Barr, Danielle Hunter and Eric Kendricks back from injuries. He knew he'd be getting nose tackle Michael Pierce back from his COVID-19 opt-out.

But he knew he needed more players, and wasn't sure what general manager Rick Spielman and Rob Brzezinski, the team's salary cap strategist, could pull off with limited cap space.

"Honestly, after the season, I was kind of down in the dumps looking at the depth chart and knowing what kind of salary cap space we had," Zimmer said. "Rob and Rick have done an unbelievably good job. They've gotten me rejuvenated with the guys they've brought in.

"And we got guys like Anthony Barr, who decides to restructure his contract because he wants to be here. We got guys like Stephen Weatherly and Mackensie and a lot of other guys who really want to be here. And Patrick Peterson. Those kinds of things get me excited. … So I'm really excited. I can't wait to get back out on the field with the players and get them going."